But he's an amazing adventurer! I let the Tick in, so Groo can join him. Despite being comedic, Groo certainly performs feats which, if they were done in our real world, would leave people speculating about technological enhancements.

By the way, Badger is also in, as he made it to issue #70! Likewise, Nexus is in, as he made it to issue #80! (Both characters had further publication afterward.)

Rom, Spaceknight would fit all the criteria but missed the cutoff by one month. The first issue of his 75 issue run came out in December 1979. Shame.